The present invention relates generally to an electrical connector and, more particularly, to an arrangement for providing electrical shielding and environmental sealing for the mating halves of an electrical connector.
The use of shielding in electrical connectors to eliminate unwanted radio frequency and electro-magnetic signals (RFI/EMI) from interfering with signals being carried by the contacts in connectors is well known. U.S. Pat. Nos. 3,521,222; 3,678,445; 4,106,839 and 4,239,318 disclose annular shields formed of sheet metal with resilient fingers which electrically engage the outer surface of the plug barrel and the inner surface of the receptacle shell of the electrical connector.
U.S. Pat. No. 3,835,443 discloses an electrical connector shield comprising a helically coiled conductive spring which is interposed between facing annualar surfaces on the mating halves of an electrical connector. The spring is coiled in such a manner that the convolutions thereof are slanted at an oblique angle of the center axis of the connector members. When the connector members are mated, the spring is axially flattened to minimize the gap between the convolutions thereof and to provide a wiping electrical engagement with the annular surfaces on the mating halves of the connector.
U.S. Pat. No. 4,033,654 discloses another form of slant coil spring shield for an electrical connector in which the spring is mounted in an internal groove formed in the receptacle shell. The convolutions of the spring are arranged in such a fashion that they will collapse radially when the plug barrel is slid into the receptacle shell.
Of course, it is well known in the art to utilize various forms of annular rings, such as O-rings, for providing environmental sealing between the mating halves of electrical connectors. However, such seals have been separate from any electrical shield which might be provided in the connector. As a consequence, separate annular grooves have been formed in the connector members in order to receive the electrical shield and the environmental sealing ring, which adds to manufacturing and assembly costs, and increasing the size of the connector assembly. Also, it is possible that the slant coil spring may be damaged during handling upon assembly of the connector or during use of the connector in the field.
It is the object of the present invention to overcome the aforementioned disadvantages of the conventional electrical shielding and sealing arrangement used for electrical connectors.
Of interest in the art of electrical shielding and environmental sealing is a composite EMI shield and environmental sealing gasket comprising a plurality of individual fine wires embedded and bonded in a solid silicone elastomer, with the wires oriented perpendicular to the mating surfaces of the product in which the gasket is installed. The manufacturer states that the wires are convoluted to allow compressing and rebounding like individual springs. Another composite shielding gasket for EMI shielding and environmental sealing utilizes a resilient knitted wire mesh strip which is mated to a silicone rubber strip wherein some of the elastomer is permitted to penetrate the porous boundary face of the wire mesh strip. In each case, the composite shielding and sealing elements are in strip or sheet form, and to our knowledge have not been shaped into closed loops for use in electrical connectors. Furthermore, the prior art gaskets do not embody any means for preventing dirt and other contaminants from reaching the conductors of the gaskets.